When I was at Uni, we put an empty can, vertical, in the machine for crushing concrete test cubes. It’s basically a big vertical vice, with 20cm square jaws, exactly parallel. The can took half a ton before crushing, concertina style buckling all the way down.
On sea kayaking trips we have a competition with empty cans, set them up on a flat rock and drop another on them, aiming to get that same concentric buckling. I’ve only done a few perfect ones, usually the wind moves the can. It has a practical benefit as well, if you can get them perfect there are no sharp corners to cut the rubbish bag.